KR20070074825A - Plane light source using leds to improve color stain characteristic and lcd backlight unit comprising the same - Google Patents

Abstract

An LED(Light Emitting Diode) surface light source and an LCD backlight unit having the same are provided to reduce color stains and decrease the number of LEDs, by disposing red, green, and blue LEDs in clusters of triangular arrangements while the LEDs are alternately inverted on a plane. A surface light source has a plurality of red, green, and blue LEDs arranged in rows and columns. The surface light source comprises a first array(20) of clusters(10) and a second array of clusters, wherein each of the clusters is composed of red, green, and blue LEDs disposed in a triangular shape. In the first array of clusters, the clusters are lined along a first direction, and inverted alternately about the first direction. In the second array of clusters, the clusters are lined along a second direction, and inverted alternately about the second direction.

Description

LED surface light source for improving color unevenness and LCD backlight unit having the same {PLANE LIGHT SOURCE USING LEDS TO IMPROVE COLOR STAIN CHARACTERISTIC AND LCD BACKLIGHT UNIT COMPRISING THE SAME}

Figure 1 (a) is a schematic diagram showing the arrangement of the LED matrix used in the conventional surface light source,

      (b) is a schematic diagram showing the LED arrangement of a surface light source employing the LED matrix shown in (a).

Figure 2 is a layout view showing the LED of the surface light source according to the prior art.

3 is a layout view showing the LED of the surface light source having the R, G, G, B device arrangement according to the prior art.

4 is a photograph showing color unevenness and white light phenomenon of an LCD backlight unit obtained by using a surface light source having a R, G, G, B device arrangement according to the prior art.

5 is a layout view showing the structure of an LED surface light source having an LED element array of a triangular cluster structure according to the first embodiment of the present invention.

6 is a photograph showing color unevenness and white light phenomenon of an LCD backlight unit obtained by using an LED surface light source for improving color unevenness according to a first embodiment of the present invention.

FIG. 7 is a layout view illustrating a structure of an LED surface light source having an LED device array having a triangular cluster structure according to a second embodiment of the present disclosure; FIG.

8 is a photograph showing color unevenness and white light phenomenon of an LCD backlight unit obtained by using an LED surface light source for improving color unevenness according to a second embodiment of the present invention.

9 is an explanatory diagram showing a correlation between a pitch interval between clusters and a diffusion sheet height in the LED plane light source according to the present invention;

10 is an exploded view showing an LCD backlight unit obtained by applying the LED surface light source according to the present invention.

       <Description of the symbols for the main parts of the drawings>

1,1 '.... LED surface light source for improving color unevenness according to the present invention

10,10 '.... Cluster 20,20' .... First Array

30,30 '.... Second Array θ1, θ2, θ3 .... Corner Angle

100 ... LCD backlight unit of the present invention 110 .... LCD panel

114 .... Condensing Sheet 116 .... Diffusion Sheet

151 .... PCB 152 .... LED

154 .... sidewalls 156 .... reflective floor

200 .... Conventional surface light source 205 .... Conventional LED matrix

211,212 .... Conventional light source edge part 300 .... Conventional surface light source

310,320,330,340 .... Conventional light source column 315 .... overlap region

400 .... Conventional Surface Light Source 410 .... First LED Array

420 ... second array of LEDs

D .... pitch spacing between clusters

H .... Height from reflector to diffuser sheet

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a surface light source for using a light emitting diode (hereinafter referred to as an LED) and to improve color spotting characteristics, and a backlight unit having a liquid crystal display device (hereinafter referred to as an LCD) including the same. LEDs that emit red, green, and blue light are arranged in clusters in triangles, but inverted in order on a plane to remove color spots and reduce the number of LEDs used to produce products at low cost. The present invention relates to an LED surface light source for improving color unevenness and an LCD backlight unit having the same.

      Cold Cathode Fluorescent Lamps (CCFLs), which are used as light sources for backlights of conventional LCDs, use mercury gas, which can cause environmental pollution, slow response, and low color reproducibility. However, it has disadvantages that are not suitable for light and small size of LCD panel.

      In comparison, LEDs are environmentally friendly, have fast response times of several nanoseconds, and are effective in video signal streams, enabling impulsive driving, over 100% color reproducibility, and the amount of red, green and blue LEDs. In addition, the brightness, color temperature, and the like can be arbitrarily changed by adjusting the size, and since the light and small size of the LCD panel are reduced, the current situation is actively adopted as a light source for backlight of LCD panels.

      In this way, the LCD backlight employing LED can be classified into an edge type backlight and a direct type backlight according to the position of the light source. The edge type backlight has a method in which a light source having a long horizontal bar is positioned at a side to irradiate light to the front of the LCD panel using a light guide plate, and the direct type is located below the LCD panel. It adopts a method of irradiating light directly to the front of the LCD panel from a surface light source having almost the same area as the LCD panel.

      The surface light source used in the conventional direct type LCD panel has a red and blue LED in one diagonal direction, as shown in FIG. 1 (a), to generate white light by mixing red, green, and blue light. The surface light source 200 which arrange | positioned and arranged two or more 2x2 LED matrix 205 by which two green LEDs were arrange | positioned in the other diagonal direction in the horizontal direction was employ | adopted.

      In the reference figure, the symbol 'R' represents a red LED emitting red light, the symbol 'G' represents a green LED emitting green light, and the symbol 'B' represents a blue LED emitting blue light. Typically two green LEDs, one red LED and a blue LED are employed to produce white light.

      The arrangement of the LEDs of the conventional surface light source 200 in which a plurality of the LED matrix 205 is arranged vertically and horizontally as described above is illustrated in FIG. 1B. In the LED arrangement as shown in (b) of FIG. 1, relatively red, green, and blue light may be smoothly mixed at the center of the surface light source 200 to generate uniform white light. Since the blue or red LEDs are not properly disposed at the 212, light having a red or blue color is emitted.

      That is, in FIG. 1 (b), only the red LED (R) and the green LED (G) are alternately arranged at the edge portion indicated by the reference numeral '211', and the blue LED (B) is not disposed, thus displaying red. (reddish) emits light, and only the blue LED (B) and the green LED (G) are alternately arranged at the edge portion indicated by the reference numeral '212', and the red LED (R) is not disposed, thus making it appear blue. (bluish) will emit light.

Therefore, the surface light source 200 employing the conventional LED arrangement has a problem that it does not emit uniform white light at the edge portion (211) (212).

      2 is a schematic diagram showing the LED arrangement of the surface light source 300 according to another conventional embodiment for solving this problem. In the cluster structure of the surface light source 300 according to the embodiment shown in FIG. 2, the plurality of LEDs are repeatedly arranged in a row in the order of blue, green, green, and red in the first column 310, The plurality of LEDs are arranged in a row in the order of green, red, blue, and green in the second column 320 adjacent to the first column 310, and then, in the third column 330, green, blue, Red and green rows are arranged, and then the fourth row 340 has a cluster structure in which red, green, green, and blue are arranged, and this structure is repeated.

      In the conventional surface light source 300 of the cluster structure, green, red, blue, and green LEDs are provided at the edge portions 311 and 312 to obtain uniform white light, but the surface light source ( In the center of 300, there is a region 315 where four green LEDs overlap, and green light is strong in such a region 315, causing color unevenness.

      The surface light source 300 having the conventional cluster arrangement as described above has a strong green distribution as a result of the light simulation, and the green light is sensitive to humans, leaving color unevenness on the surface light source.

      Therefore, in the conventional surface light source 300 and the LCD backlight unit employing the same, there is a problem that color unevenness exists so that a uniform distribution of desirable white light cannot be obtained.

In order to solve such a problem, the applicant of the present invention solved the problem of such color unevenness in Korean Patent Application No. 2005-62297.

Such a prior art by the applicant of the present invention, as shown in Figure 3, adjacent to the first green LED array 410 and adjacent adjacent to the first LED array 410 arranged one red LED and blue LED Two green LEDs, and second LED arrays 420, which in turn are arranged adjacent one blue LED and red LEDs, wherein the first and second LED arrays 410, 420 are in an arbitrary row. Or arranged in rows, wherein the first and second LED arrays 410 and 420 provide a surface light source 400 in which the LEDs surrounding the two green LEDs are made of red or blue LEDs.

In the conventional surface light source 400 as described above, as shown in Figure 4, LEDs emitting red, green and blue light is arranged, LEDs surrounding the two green LEDs are made of a red or blue LED By doing so, it is possible to obtain an excellent effect of generating uniform white light with almost no color unevenness in the center portion of the surface light source 400. In addition, this conventional technique is to obtain a uniform white light by making the white light emitted from the surface light source 400 is similar to the human color sense map so that less color unevenness appears.

However, such a conventional technique uses two adjacent green LEDs and clusters of adjacent one red and blue LEDs, that is, four B, G, G, and R elements as one unit unit. The number of LEDs required per unit area of the surface light source 400 was large. Therefore, such a conventional technique has room for improvement in terms of implementing a low cost surface light source.

The present invention is to solve the conventional problems as described above, the object of the present invention is to provide a LED surface light source and color LED backlight unit for improving the color spots that can generate a uniform white light by removing the color spots phenomenon. .

Another object of the present invention is to provide an LED surface light source for improving color unevenness, which can reduce the number of LEDs used per unit area of a surface light source and obtain excellent white light while producing a product at low cost, and an LCD backlight unit having the same. .

The present invention to achieve the above object,

In a surface light source in which a plurality of G, R, B LED elements are arranged in rows and columns,

A first array having a plurality of clusters in which the G, R, and B LED elements are arranged in a triangle and inverted in the center in the first direction along the first direction of the clusters; And

And a second array having a plurality of clusters in which the G, R, and B LED elements are arranged in a triangle, and inverted to be inverted about the second direction along a second direction of the clusters.

The first and second arrays are orthogonal to each other to provide an LED surface light source for improving color unevenness.

In addition, the present invention provides the LED surface light source for improving color spots, wherein each of the clusters is formed with the same corner angles that each LED element forms with respect to each other.

In another aspect, the present invention provides an LED surface light source for improving color spots, characterized in that each of the clusters are formed with different corner angles formed by the respective LED elements with respect to each other.

In addition, the present invention provides the LED surface light source for improving color unevenness, characterized in that each of the clusters are formed in the same two of each of the corner angles that each LED element is formed with respect to each other.

In addition, the present invention preferably, each of the clusters LED corner light source for improving color spots, characterized in that the corner angles formed by the respective LED elements with respect to each other are formed correspondingly to the corner angles of the adjacent clusters to provide.

And the present invention preferably, the pitch interval between the clusters, when configuring the LCD backlight unit, LED for improving color spots, characterized in that the range of D≤2H for the height from the reflecting plate to the diffusion sheet Provide cotton light source.

In addition, the present invention to achieve the above object,

In the LCD backlight unit attached to the LCD panel,

G, R, B LED elements having a plurality of clusters arranged in a triangle, the first array and the G, R, B LED elements are inverted arranged in turn about the first direction along the first direction of the clusters And a second array having a plurality of clusters arranged in a triangle, the second array being inverted in turn about the second direction along the second direction of the clusters, wherein the first array and the second array are orthogonal to each other. ;

A diffusion sheet for uniformly diffusing the light incident from the surface light source; And

It provides a LCD backlight unit comprising a; condensing sheet for collecting light diffused from the diffusion sheet.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 5, the LED surface light source 1 for improving color unevenness according to the first embodiment of the present invention includes a plurality of clusters 10 in which G, R, and B LED elements are arranged in a triangle. The first array 20 may be inverted in order with respect to the first direction along the first direction of the clusters 10.

That is, as shown in FIG. 5, it is assumed that the X axis is the first direction and the Y axis is the second direction.

In this case, the plurality of clusters 10 positioned in the first array 20 have an arrangement structure inverted up and down about the first direction along the first direction of the X axis.

Therefore, in the first array 20 of FIG. 4, if the G, R, and B LED elements located in the first cluster 10 have a G element positioned at the upper side and R and B elements positioned at the lower side, In the second cluster 10, the G, R, and B LED elements are located at the upper side of the R and B elements and at the lower side of the G element. And the G, R, B LED elements located in the third cluster 10 have G elements located at the upper side, R and B elements located at the lower side, and located at the fourth cluster 10. The G, R, and B LED elements, like the second one, have R and B elements on the upper side and G elements on the lower side.

In addition, the second array 30 arranged to be orthogonal to the first array 20 as described above may include a plurality of clusters in which the G, R, and B LED elements are arranged in a triangle like the first array 20. 10) and inverted in sequence with respect to the second direction along the second direction of the clusters 10.

That is, as shown in FIG. 5, when the Y axis is assumed to be the second direction, the plurality of clusters 10 positioned in the second array 30 may be moved to the left and right about the second direction along the second direction of the Y axis. It has an inverted arrangement structure.

Therefore, in the second array 30 of FIG. 5, the G, R, and B LED elements located in the first cluster 10 are positioned with the G element at the upper side, the R element at the left side, and the B at the right side. If the elements are located, the G, R, B LED elements located in the second cluster 10 have G elements located on the upper side, B elements on the left side, and R elements on the right side. Structure.

And the G, R, B LED elements located in the third cluster 10 have G elements located at the upper side, R and B elements located at the lower side, and located at the fourth cluster 10. The G, R, and B LED elements, like the second one, are also positioned with the G element on the upper side, the B element on the left side on the lower side, and the R elements on the right side.

In addition, the LED surface light source 1 for improving color spotting according to the present invention is that each of the clusters 10 have the same corner angles θ1, θ2, and θ3 that each LED element forms with respect to each other. Formed. In this case, the G, R, and B LED elements included in one cluster 10 forming one unit unit may be arranged in one equilateral triangle structure.

In the present invention, each of the clusters 10 may have different corner angles θ1, θ2, and θ3 formed by the respective LED elements with respect to each other. In this case, the G, R, and B LED elements included in one cluster 10 forming one unit unit may be arranged in a general triangular structure with different corner angles.

In addition, in the present invention, each of the clusters 10 may have two corner angles θ1, θ2, and θ3 that each LED element forms with respect to each other. In this case, the G, R, and B LED elements included in one cluster 10 forming one unit unit may be arranged in an isosceles triangle structure.

In addition, the surface light source according to the present invention is a corner angle (θ1) (θ2) (θ3) formed by each LED element provided in each of the cluster 10 with respect to each other (the corner angle of the cluster 10 adjacent thereto ( The same is formed in correspondence with θ1), θ2, and θ3. That is, the surface light source according to the present invention is a triangle formed by the G, R, B LED elements included in one unit cluster 10 formed over the first array 20 and the second array 30 are all Same thing.

When the LED surface light source 1 for improving color spots according to the present invention configured as described above is configured with the LCD backlight unit 100 as shown in FIG. 6, color spots are eliminated and uniform white light can be obtained. The LED surface light source 1 for improving color unevenness according to the present invention has a color unevenness and a uniform surface as obtained from the surface light source 400 of Korean Patent Application No. 2005-62297 filed by the applicant of the present invention. You can get a light source.

7 illustrates another structure of the LED surface light source 1 ′ for improving color unevenness according to the second embodiment of the present invention.

Such a structure has a first array 20 'and a second array 30' as shown in FIG. 5, but each of the G, R, and B LED elements included in one unit cluster 10 ' The distance between the LED elements of is closely formed, and the distance between one cluster 10 'and the cluster 10' is arranged farther than the structure shown in FIG.

In the structure of the present invention, the pitch interval D between the clusters 10 'is the diffusion sheet 116 from the reflecting plate 156 when the LCD backlight unit 100 is configured, as shown in FIG. It has a range of D≤2H for height H up to). If the pitch spacing D between the clusters 10 exceeds 2H, the distance between the clusters 10 may be too long, resulting in a lack of light, thereby forming color spots. It is not desirable because there is.

In the case of the LED surface light source 1 ′ according to the present invention having the above structure, when the LCD backlight unit 100 is configured, there is no color unevenness as shown in FIG. 8, thereby obtaining uniform white light. The LED surface light source 1 ′ of the present invention also has a low color unevenness as obtained by the surface light source 400 of Korean Patent Application No. 2005-62297 filed by the applicant of the present invention, so that uniform white light can be obtained. will be.

On the other hand, the LED surface light source (1) (1 ') for improving color unevenness according to the present invention has a structure as shown in Figure 10 when configuring the LCD backlight unit 100.

The LCD backlight unit 100 according to the embodiment of the present invention includes the surface light source 1 according to the present invention as described above, and a diffusion sheet for uniformly diffusing the light incident from the surface light source 1 ( 116).

      At least one light collecting sheet provided on the LCD panel 110 side of the diffusion sheet 116 and condensing the light diffused from the diffusion sheet 116 in a direction perpendicular to the plane of the LCD panel 110 ( 114) and the like.

In the above, the pitch interval D between the clusters 10 provided in the surface light source 1 has a range of D ≦ 2H with respect to the height H from the reflecting plate to the diffusion sheet as described above.

In addition, the LCD backlight unit 100 according to the present invention may be disposed on the light collecting sheet 114 and further include a protective sheet 112 for protecting the lower optical structure. In addition, the surface light source 1 includes a substrate 151 and a plurality of LEDs 152 disposed on the substrate 151 in the above-described cluster 10 structure. In addition, the sidewall 154 is formed to surround the LED 152 arranged in the cluster 10 structure of the present invention at the edge of the upper surface of the substrate 151, the side wall 154 having an inclined surface in the direction in which the LED 152 is disposed And a reflective layer 156 formed on an upper surface of the substrate 151 to reflect light emitted from the LED 152 to the top.

      In addition, the reflective material 154a is preferably applied to the inclined surface of the side wall 154 so as to emit light emitted in the lateral direction.

      In addition, the diffusion sheet 116 disposed above the surface light source 1 prevents light from being partially concentrated by dispersing the light incident from the surface light source 1. In addition, the diffusion sheet 116 also serves to reduce the inclination angle with respect to the first light collecting sheet 114a by adjusting the direction of light traveling toward the first light collecting sheet 114a.

      The first condensing sheet 114a and the second condensing sheet 114b are formed on the upper surface of the first condensing sheet 114a with a triangular prism-shaped array, respectively, and the prism arrangement of the first condensing sheet 114a and the second condensing sheet 114a. The prism arrays of the light collecting sheets 114b are arranged to be staggered with each other at a predetermined angle (for example, 90 °). The first and second light collecting sheets 114a and 214b respectively collect light diffused from the diffusion sheet 116 in a direction perpendicular to a plane of the LCD panel 110. And the perpendicular incidence of the light passing through the second light collecting sheets 114a and 214b to the protective sheet 112 is almost completely obtained.

As a result, the light passing through the first and second light collecting sheets 114a and 214b almost passes vertically, so that the luminance distribution on the protective sheet 112 is uniformly obtained.

Meanwhile, the present invention illustrates an example of using two light collecting sheets in FIG. 10, but in some cases, only one light collecting sheet may be used.

The protective sheet 112 formed on the second light collecting sheet 114b not only serves to protect the surface of the second light collecting sheet 114b, but also diffuses light in order to uniformize the light distribution. Play a role of The LCD panel 110 is installed on the protective sheet 112.

     As such, the LCD backlight unit 100 according to the present invention includes the surface light source 1 according to the present invention to remove color unevenness and thus obtain uniform white light as a whole. The structure can be reduced, and it is suitable for light weight and slimness, and can provide clear images.

As described above, according to the present invention, it is possible to generate uniform white light by removing color unevenness, and to reduce the number of LEDs by 25% compared to the structure of the conventional R, G, G, and B devices. will be.

Therefore, according to the present invention, it is possible to reduce the number of LEDs used per unit area of the surface light source and to obtain an effect of obtaining excellent white light while producing a product at low cost.

While the invention has been shown and described with respect to specific embodiments thereof, it has been described by way of example only to illustrate the invention, and is not intended to limit the invention to this particular structure. Those skilled in the art will appreciate that various modifications and changes of the present invention can be made without departing from the spirit and scope of the invention as set forth in the claims below. Nevertheless, it will be clearly understood that all such modifications and variations are included within the scope of the present invention.

Claims (10)

In a surface light source in which a plurality of G, R, B LED elements are arranged in rows and columns, A first array having a plurality of clusters in which the G, R, and B LED elements are arranged in a triangle and inverted in the center in the first direction along the first direction of the clusters; And And a second array having a plurality of clusters in which the G, R, and B LED elements are arranged in a triangle, and inverted to be inverted about the second direction along a second direction of the clusters. The LED surface light source for improving color spots, characterized in that the first array and the second array is orthogonal to each other. The LED surface light source of claim 1, wherein the first array is arranged inverted up and down alternately. The LED surface light source of claim 1, wherein the second arrays are arranged inverted left and right alternately. The LED surface light source of claim 1, wherein each of the clusters has the same corner angles formed by the respective LED elements with respect to each other. The LED surface light source of claim 1, wherein each of the clusters has different corner angles formed by the respective LED elements with respect to each other. The LED surface light source of claim 1, wherein each of the clusters has two corner angles formed by the respective LED elements with respect to each other. The color spot enhancement according to any one of claims 1 to 6, wherein each of the clusters has the same corner angles formed by the respective LED elements with respect to each other to correspond to corner angles of adjacent clusters. Cotton light source for home. The method according to any one of claims 1 to 6, wherein, when the clusters constitute an LCD backlight unit, the pitch interval therebetween has a range of D≤2H for the height from the reflecting plate to the diffusion sheet. LED cotton light source for improving color staining. In the LCD backlight unit attached to the LCD panel, G, R, B LED elements having a plurality of clusters arranged in a triangle, the first array and the G, R, B LED elements are inverted arranged in turn about the first direction along the first direction of the clusters And a second array having a plurality of clusters arranged in a triangle, the second array being inverted in turn about the second direction along the second direction of the clusters, wherein the first array and the second array are orthogonal to each other. ; A diffusion sheet for uniformly diffusing the light incident from the surface light source; And And a light collecting sheet for collecting light diffused from the diffusion sheet. 10. The LCD backlight unit of claim 9, wherein when the clusters constitute an LCD backlight unit, the pitch interval therebetween is in a range of D≤2H with respect to the height from the reflecting plate to the diffusion sheet.

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